Point-of-care ultrasound (POCUS) protocol for systematic assessment of the crashing neonate-expert consensus statement of the international crashing neonate working group.

Sudden unexpected clinical deterioration or cardiorespiratory instability is common in neonates and is often referred as a "crashing" neonate. The established resuscitation guidelines provide an excellent framework to stabilize and evaluate these infants, but it is primarily based upon clinical assessment only. However, clinical assessment in sick neonates is limited in identifying underlying pathophysiology. The Crashing Neonate Protocol (CNP), utilizing point-of-care ultrasound (POCUS), is specifically designed for use in neonatal emergencies. It can be applied both in term and pre-term neonates in the neonatal intensive care unit (NICU). The proposed protocol involves a stepwise systematic assessment with basic ultrasound views which can be easily learnt and reproduced with focused structured training on the use of portable ultrasonography (similar to the FAST and BLUE protocols in adult clinical practice). We conducted a literature review of the evidence-based use of POCUS in neonatal practice. We then applied stepwise voting process with a modified DELPHI strategy (electronic voting) utilizing an international expert group to prioritize recommendations. We also conducted an international survey among a group of neonatologists practicing POCUS. The lead expert authors identified a specific list of recommendations to be included in the proposed CNP. This protocol involves pre-defined steps focused on identifying the underlying etiology of clinical instability and assessing the response to intervention.Conclusion: To conclude, the newly proposed POCUS-based CNP should be used as an adjunct to the current recommendations for neonatal resuscitation and not replace them, especially in infants unresponsive to standard resuscitation steps, or where the underlying cause of deterioration remains unclear. What is known? • Point-of-care ultrasound (POCUS) is helpful in evaluation of the underlying pathophysiologic mechanisms in sick infants. What is new? • The Crashing Neonate Protocol (CNP) is proposed as an adjunct to the current recommendations for neonatal resuscitation, with pre-defined steps focused on gaining information regarding the underlying pathophysiology in unexplained "crashing" neonates. • The proposed CNP can help in targeting specific and early therapy based upon the underlying pathophysiology, and it allows assessment of the response to intervention(s) in a timely fashion.

A Randomized Placebo-Controlled Pilot Trial of Early Targeted Nonsteroidal Anti-Inflammatory Drugs in Preterm Infants with a Patent Ductus Arteriosus.

OBJECTIVE: To establish the feasibility of a future large randomized trial to compare early treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) while awaiting spontaneous patent ductus arteriosus (PDA) closure. STUDY DESIGN: Preterm infants at <29 weeks of gestation with a PDA diameter >1.5 mm and <72 hours after birth were randomized to NSAIDs vs placebo. No open-label NSAID treatment was allowed in either arm, but all infants with PDA volume load received supportive management, including optimization of airway pressure, careful fluid management, and diuretics as needed. The pilot outcomes were recruitment rate and incidence of open-label treatment. Secondary clinical outcomes included chronic lung disease or death, the planned primary outcome for a future large trial. RESULTS: Overall, 54% of the approached parents consented to participate in the study. The median recruitment rate was 3 infants per month, and a total of 72 infants were randomized. One patient in each arm received open-label treatment. PDA closure rates were 74% for the NSAIDs arm vs 30% for the placebo arm, but this was not associated with significant changes in clinical outcomes. CONCLUSIONS: This pilot trial showed that recruitment of more than one-half of eligible infants with a low incidence of open-label treatment is feasible. PDA closure rates and clinical outcomes were similar to those reported in previous PDA trials.

Delayed versus Immediate Cord Clamping in Preterm Infants.

BACKGROUND: The preferred timing of umbilical-cord clamping in preterm infants is unclear. METHODS: We randomly assigned fetuses from women who were expected to deliver before 30 weeks of gestation to either immediate clamping of the umbilical cord (≤10 seconds after delivery) or delayed clamping (≥60 seconds after delivery). The primary composite outcome was death or major morbidity (defined as severe brain injury on postnatal ultrasonography, severe retinopathy of prematurity, necrotizing enterocolitis, or late-onset sepsis) by 36 weeks of postmenstrual age. Analyses were performed on an intention-to-treat basis, accounting for multiple births. RESULTS: Of 1634 fetuses that underwent randomization, 1566 were born alive before 30 weeks of gestation; of these, 782 were assigned to immediate cord clamping and 784 to delayed cord clamping. The median time between delivery and cord clamping was 5 seconds and 60 seconds in the respective groups. Complete data on the primary outcome were available for 1497 infants (95.6%). There was no significant difference in the incidence of the primary outcome between infants assigned to delayed clamping (37.0%) and those assigned to immediate clamping (37.2%) (relative risk, 1.00; 95% confidence interval, 0.88 to 1.13; P=0.96). The mortality was 6.4% in the delayed-clamping group and 9.0% in the immediate-clamping group (P=0.03 in unadjusted analyses; P=0.39 after post hoc adjustment for multiple secondary outcomes). There were no significant differences between the two groups in the incidences of chronic lung disease or other major morbidities. CONCLUSIONS: Among preterm infants, delayed cord clamping did not result in a lower incidence of the combined outcome of death or major morbidity at 36 weeks of gestation than immediate cord clamping. (Funded by the Australian National Health and Medical Research Council [NHMRC] and the NHMRC Clinical Trials Centre; APTS Australian and New Zealand Clinical Trials Registry number, ACTRN12610000633088 .).

Method of Blood Pressure Measurement in Neonates and Infants: A Systematic Review and Analysis.

OBJECTIVES: To determine the recommended blood pressure (BP) measurement methods in neonates after systematically analyzing the literature regarding proper BP cuff size and measurement location and method. STUDY DESIGN: A literature search was conducted in MEDLINE, PubMed, Embase, Cochrane Library, and CINAHL from 1946 to 2017 on BP in neonates <3 months of age (PROSPERO ID CRD42018092886). Study data were extracted and analyzed with separate analysis of Bland-Altman studies comparing measurement methods. RESULTS: Of 3587 nonduplicate publications identified, 34 were appropriate for inclusion in the analysis. Four studies evaluating BP cuff size support a recommendation for a cuff width to arm circumference ratio of approximately 0.5. Studies investigating measurement location identified the upper arm as the most accurate and least variable location for oscillometric BP measurement. Analysis of studies using Bland-Altman methods for comparison of intra-arterial to oscillometric BP measurement show that the 2 methods correlate best for mean arterial pressure, whereas systolic BP by the oscillometric method tends to overestimate intra-arterial systolic BP. Compared with intra-arterial methods, systolic BP, diastolic BP, and mean arterial pressure by oscillometric methods are less accurate and precise, especially in neonates with a mean arterial pressure <30 mm Hg. CONCLUSIONS: Proper BP measurement is critical in neonates with naturally lower BP and attention to BP cuff size, location, and method of measurement are essential. With decreasing use of intra-arterial catheters for long-term BP monitoring in neonates, further studies are urgently needed to validate and develop oscillometric methodology with enhanced accuracy.

Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants.

BACKGROUND: The safest ranges of oxygen saturation in preterm infants have been the subject of debate. METHODS: In two trials, conducted in Australia and the United Kingdom, infants born before 28 weeks' gestation were randomly assigned to either a lower (85 to 89%) or a higher (91 to 95%) oxygen-saturation range. During enrollment, the oximeters were revised to correct a calibration-algorithm artifact. The primary outcome was death or disability at a corrected gestational age of 2 years; this outcome was evaluated among infants whose oxygen saturation was measured with any study oximeter in the Australian trial and those whose oxygen saturation was measured with a revised oximeter in the U.K. trial. RESULTS: After 1135 infants in Australia and 973 infants in the United Kingdom had been enrolled in the trial, an interim analysis showed increased mortality at a corrected gestational age of 36 weeks, and enrollment was stopped. Death or disability in the Australian trial (with all oximeters included) occurred in 247 of 549 infants (45.0%) in the lower-target group versus 217 of 545 infants (39.8%) in the higher-target group (adjusted relative risk, 1.12; 95% confidence interval [CI], 0.98 to 1.27; P=0.10); death or disability in the U.K. trial (with only revised oximeters included) occurred in 185 of 366 infants (50.5%) in the lower-target group versus 164 of 357 infants (45.9%) in the higher-target group (adjusted relative risk, 1.10; 95% CI, 0.97 to 1.24; P=0.15). In post hoc combined, unadjusted analyses that included all oximeters, death or disability occurred in 492 of 1022 infants (48.1%) in the lower-target group versus 437 of 1013 infants (43.1%) in the higher-target group (relative risk, 1.11; 95% CI, 1.01 to 1.23; P=0.02), and death occurred in 222 of 1045 infants (21.2%) in the lower-target group versus 185 of 1045 infants (17.7%) in the higher-target group (relative risk, 1.20; 95% CI, 1.01 to 1.43; P=0.04). In the group in which revised oximeters were used, death or disability occurred in 287 of 580 infants (49.5%) in the lower-target group versus 248 of 563 infants (44.0%) in the higher-target group (relative risk, 1.12; 95% CI, 0.99 to 1.27; P=0.07), and death occurred in 144 of 587 infants (24.5%) versus 99 of 586 infants (16.9%) (relative risk, 1.45; 95% CI, 1.16 to 1.82; P=0.001). CONCLUSIONS: Use of an oxygen-saturation target range of 85 to 89% versus 91 to 95% resulted in nonsignificantly higher rates of death or disability at 2 years in each trial but in significantly increased risks of this combined outcome and of death alone in post hoc combined analyses. (Funded by the Australian National Health and Medical Research Council and others; BOOST-II Current Controlled Trials number, ISRCTN00842661, and Australian New Zealand Clinical Trials Registry number, ACTRN12605000055606.).

Associations of measures of systemic blood flow used in a randomized trial of delayed cord clamping in preterm infants.

OBJECTIVE: To determine associations of low superior vena cava (SVC) flow (≤55 ml/kg/min) and low right ventricular output (RVO) (≤150 ml/kg/min) in preterm infants. DESIGN/METHODS: An observational study in infants <30 weeks gestation randomized to receive immediate (<10 s) or delayed cord clamping (DCC) (≥60 s). RESULTS: The study enrolled 265 infants with a mean (SD) gestation 28 (2) weeks. Eighty-six (33%) infants had low SVC flow and 81 (31%) infants had low RVO. In multivariate analysis, low SVC flow was associated with gestation; low RVO was associated with DCC, gender and 5-minute Apgar; whereas mean RVO was negatively associated with both FiO2 and mean airway pressure (MAP) at 9 h and 24 h. Low SVC flow was associated with ductus arteriosus (DA) treatment. Infants with low RVO had higher mortality on univariate analysis, but this was not significant after adjusting for gestation. CONCLUSIONS: SVC flow was associated with gestation, whilst RVO was associated with placental transfusion, gender, condition at birth, and early respiratory adaptation. Compared to infants with normal values, more infants with low SVC flow were treated for DA, but infants with low RVO had no significant difference in mortality or morbidity.

Correction: Associations of measures of systemic blood flow used in a randomized trial of delayed cord clamping in preterm infants.

A correction to this paper has been published and can be accessed via a link at the top of the paper.

The Effect of Antenatal Betamethasone on White Matter Inflammation and Injury in Fetal Sheep and Ventilated Preterm Lambs.

Antenatal administration of betamethasone (BM) is a common antecedent of preterm birth, but there is limited information about its impact on the acute evolution of preterm neonatal brain injury. We aimed to compare the effects of maternal BM in combination with mechanical ventilation on the white matter (WM) of late preterm sheep. At 0.85 of gestation, pregnant ewes were randomly assigned to receive intra-muscular (i.m.) saline (n = 9) or i.m. BM (n = 13). Lambs were delivered and unventilated controls (UVCSal, n = 4; UVCBM, n = 6) were humanely killed without intervention; ventilated lambs (VentSal, n = 5; VentBM, n = 7) were injuriously ventilated for 15 min, followed by conventional ventilation for 75 min. Cardiovascular and cerebral haemodynamics and oxygenation were measured continuously. The cerebral WM underwent assessment of inflammation and injury, and oxidative stress was measured in the cerebrospinal fluid (CSF). In the periventricular and subcortical WM tracts, the proportion of amoeboid (activated) microglia, the density of astrocytes, and the number of blood vessels with protein extravasation were higher in UVCBM than in UVCSal (p < 0.05 for all). During ventilation, tidal volume, mean arterial pressure, carotid blood flow, and oxygen delivery were higher in -VentBM lambs (p < 0.05 vs. VentSal). In the subcortical WM, microglial infiltration was increased in the VentSal group compared to UVCSal. The proportion of activated microglia and protein extravasation was higher in the VentBM group compared to VentSal within the periventricular and subcortical WM tracts (p < 0.05). CSF oxidative stress was increased in the VentBM group compared to UVCSal, UVCBM, and VentSal groups (p < 0.05). Antenatal BM was associated with inflammation and vascular permeability in the WM of late preterm fetal sheep. During the immediate neonatal period, the increased carotid perfusion and oxygen delivery in BM-treated lambs was associated with increased oxidative stress, microglial activation and microvascular injury.

Feasibility and utility of portable ultrasound during retrieval of sick preterm infants.

AIM: Document the incidence of haemodynamic pathology in critically ill preterm newborns requiring transport. METHOD: A transport neonatologist performed cardiac and cerebral ultrasound before and after transportation of infants born ≤30 weeks gestation. RESULTS: Forty-four newborns were studied in 2008-2015; of them, 21 were transported by road, 19, by helicopter and four, by fixed wing: median birthweight, 1130 g (680-1960 g) and median gestation, 27 weeks (23-30); 30 of 44 were male babies. Antenatal steroid course was complete in two babies. Ultrasound in the referring hospital was at a mean of two hours: 47 minutes (00:15-7:00) of age. Low systemic blood flow was common: 50% had right ventricular output <150mL/kg/min and 23%, a superior vena cava flow <50mL/kg/min. at stabilisation. Cranial US: 10 Grade I IVH, 2 Grade II IVH, 1 Grade IV IVH and 32 normal scans pretransport. After transport, three further Grade I IVH were reported. Mortality was higher in the babies with low systemic blood flow: 4 of 12 (33%) died vs 1 of 31 (6%) in the normal flow group (OR = 7.2, 95% CI: 1.1 to 47, p = 0.022). CONCLUSION: Point-of-care ultrasound during the retrieval of preterm infants confirms a high incidence of haemodynamic pathology. The use of ultrasound during transport may provide an opportunity for earlier targeted circulatory support.

Ventilation-induced lung injury is not exacerbated by growth restriction in preterm lambs.

Intrauterine growth restriction (IUGR) and preterm birth are frequent comorbidities and, combined, increase the risk of adverse respiratory outcomes compared with that in appropriately grown (AG) infants. Potential underlying reasons for this increased respiratory morbidity in IUGR infants compared with AG infants include altered fetal lung development, fetal lung inflammation, increased respiratory requirements, and/or increased ventilation-induced lung injury. IUGR was surgically induced in preterm fetal sheep (0.7 gestation) by ligation of a single umbilical artery. Four weeks later, preterm lambs were euthanized at delivery or delivered and ventilated for 2 h before euthanasia. Ventilator requirements, lung inflammation, early markers of lung injury, and morphological changes in lung parenchymal and vascular structure and surfactant composition were analyzed. IUGR preterm lambs weighed 30% less than AG preterm lambs, with increased brain-to-body weight ratio, indicating brain sparing. IUGR did not induce lung inflammation or injury or alter lung parenchymal and vascular structure compared with AG fetuses. IUGR and AG lambs had similar oxygenation and respiratory requirements after birth and had significant, but similar, increases in proinflammatory cytokine expression, lung injury markers, gene expression, and surfactant phosphatidylcholine species compared with unventilated controls. IUGR does not induce pulmonary structural changes in our model. Furthermore, IUGR and AG preterm lambs have similar ventilator requirements in the immediate postnatal period. This study suggests that increased morbidity and mortality in IUGR infants is not due to altered lung tissue or vascular structure, or to an altered response to early ventilation.

Effect of Delayed Cord Clamping on Systemic Blood Flow: A Randomized Controlled Trial.

OBJECTIVE: To determine whether delayed cord clamping improves systemic blood flow compared with immediate cord clamping in very preterm infants in the first 24 hours. STUDY DESIGN: Women delivering at <30 weeks' gestation at 5 tertiary centers were randomized to receive immediate cord clamping (<10 seconds) or delayed cord clamping (≥60 seconds). Echocardiography and cardiorespiratory data were collected at 3, 9, and 24 hours after birth. The primary outcome was mean lowest superior vena cava (SVC) flow. RESULTS: Of 266 infants enrolled, 133 were randomized to immediate cord clamping and 133 to delayed cord clamping. The 2 groups were similar at baseline, including mean gestation (immediate cord clamping 28 weeks vs delayed cord clamping 28 weeks) and birth weight (immediate cord clamping 1003 g vs delayed cord clamping 1044 g). There was no significant difference between groups in the primary outcome of mean lowest SVC flow (immediate cord clamping 71.4 mL/kg/min [SD 28.1] vs delayed cord clamping 70.2 mL/kg/min [SD 26.9]; P = .7). For secondary outcomes, hemoglobin increased by 0.9 g/dL at 6 hours in the group with delayed cord clamping (95% CI 3.9, 14.4; P = .0005, adjusted for baseline). The group with delayed cord clamping had lower right ventricular output (-21.9 mL/kg/min, 95% CI -39.0, -4.7; P = .01). Rates of treated hypotension, ductus arteriosus size and shunt direction, and treatment of the ductus arteriosus were similar. CONCLUSIONS: Delayed cord clamping had no effect on systemic blood flow measured as mean lowest SVC flow in the first 24 hours in infants <30 weeks' gestation. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry: ACTRN12610000633088.

Altered cardiovascular function at birth in growth-restricted preterm lambs.

BACKGROUND: Cardiovascular dysfunction at birth may underlie poor outcomes after fetal growth restriction (FGR) in neonates. We compared the cardiovascular transition between FGR and appropriately grown (AG) preterm lambs and examined possible mechanisms underlying any cardiovascular dysfunction in FGR lambs. METHODS: FGR was induced in ewes bearing twins at 0.7 gestation; the twin was used as an internal control (AG). At 0.8 gestation, lambs were delivered and either euthanized with their arteries isolated for in vitro wire myography, or ventilated for 2 h. At 60 min, inhaled nitric oxide (iNO) was administered in a subgroup for 30 min. Molecular assessment of the nitric oxide (NO) pathway within lung tissue was conducted. RESULTS: FGR lambs had lower left ventricular output and cerebral blood flow (CBF) and higher systemic vascular resistance compared with AG lambs. INO administration to FGR lambs rapidly improved cardiovascular and systemic hemodynamics but resulted in decreased CBF in AG lambs. Isolated arteries from FGR lambs showed impaired sensitivity to NO donors, but enhanced vasodilation to Sildenafil and Sodium nitroprusside, and altered expression of components of the NO pathway. CONCLUSION: Cardiovascular dysfunction at birth may underlie the increased morbidity and mortality observed in preterm FGR newborns. Impaired NO signaling likely underlies the abnormal vascular reactivity.

Oxygen saturation profile of term equivalent extreme preterm infants at discharge - comparison with healthy term counterparts.

AIM: Compare the oxygen saturation profiles before discharge of neonates born extremely preterm (<28 weeks), now at term equivalent age, with healthy term neonates and assess the impact of feeding on this profile in each group. METHODS: We prospectively evaluated and compared the oxygen saturation profile in 15 very low birthweight infants at term equivalent age, ready to be discharged home without any oxygen and 15 term newborns after 48 hours of life. We also evaluated and compared the saturations of these two groups during a one-hour period during and after feeding. RESULTS: Term equivalent preterm and term infants spent median 3% and 0%, respectively, of the time below 90% in a 12-hour saturation-recording period. Term infants spent a median 0.26% and 0.65% of the time in <90% saturation during feed time and no feed time, respectively. In contrast, preterm infants spent significantly more time <90% saturation (3.47% and 3.5% during feed time and no feed time, respectively). CONCLUSION: Term equivalent preterm infants spent significantly more time in a saturation range <90% compared to term infants. Feeding had little effect on saturation profile overall within each group.

Feasibility and utility of portable ultrasound during retrieval of sick term and late preterm infants.

AIM: To determine the role of clinician performed ultrasound (CPU) during the retrieval and transport of critically ill term and near term newborns. METHODS: A neonatologist with portable ultrasound accompanied a sample of newborn retrievals to perform cardiac and cerebral ultrasound before and after transportation. RESULTS: A total of fifty-five babies were studied. Median birthweight: 3350 g (2220-5030 g). CPU led to a change in the planned receiving hospital in ten babies. Eleven babies were suspected congenital heart disease (CHD) prior to retrieval: eight confirmed CHD by CPU and three normal structure. One transported to a children's hospital for cardiology review was confirmed as having normal structure; one to a perinatal hospital where normal structure was confirmed and one baby died at the referring hospital and postmortem confirmed normal structure. In five babies with clinical pulmonary hypertension, CPU revealed unsuspected CHD. The destination was changed to a paediatric cardiology centre, avoiding a second retrieval. Eleven babies had evidence of haemodynamic compromise allowing targeting of inotropes. CONCLUSION: This is the first study of CPU during retrieval of high-risk infants. Ultrasound in retrieval is feasible, allows accurate triage of babies to cardiac centres and may allow more accurate targeting of fluid and inotrope support.

Lung ultrasound accurately detects pneumothorax in a preterm newborn lamb model.

AIM: Pneumothorax is a common emergency affecting extremely preterm. In adult studies, lung ultrasound has performed better than chest x-ray in the diagnosis of pneumothorax. The purpose of this study was to determine the efficacy of lung ultrasound (LUS) examination to detect pneumothorax using a preterm animal model. METHODS: This was a prospective, observational study using newborn Border-Leicester lambs at gestational age = 126 days (equivalent to gestational age = 26 weeks in humans) receiving mechanical ventilation from birth to 2 h of life. At the conclusion of the experiment, LUS was performed, the lambs were then euthanised and a post-mortem exam was immediately performed. We used previously published ultrasound techniques to identify pneumothorax. Test characteristics of LUS to detect pneumothorax were calculated, using the post-mortem exam as the 'gold standard' test. RESULTS: Nine lambs (18 lungs) were examined. Four lambs had a unilateral pneumothorax, all of which were identified by LUS with no false positives. CONCLUSIONS: This was the first study to use post-mortem findings to test the efficacy of LUS to detect pneumothorax in a newborn animal model. Lung ultrasound accurately detected pneumothorax, verified by post-mortem exam, in premature, newborn lambs.

Cardiovascular transition at birth: a physiological sequence.

The transition to newborn life at birth involves major cardiovascular changes that are triggered by lung aeration. These include a large increase in pulmonary blood flow (PBF), which is required for pulmonary gas exchange and to replace umbilical venous return as the source of preload for the left heart. Clamping the umbilical cord before PBF increases reduces venous return and preload for the left heart and thereby reduces cardiac output. Thus, if ventilation onset is delayed following cord clamping, the infant is at risk of superimposing an ischemic insult, due to low cardiac output, on top of an asphyxic insult. Much debate has centered on the timing of cord clamping at birth, focusing mainly on the potential for a time-dependent placental to infant blood transfusion. This has prompted recommendations for delayed cord clamping for a set time after birth in infants not requiring resuscitation. However, recent evidence indicates that ventilation onset before cord clamping mitigates the adverse cardiovascular consequences caused by immediate cord clamping. This indicates that the timing of cord clamping should be based on the infant's physiology rather than an arbitrary period of time and that delayed cord clamping may be of greatest benefit to apneic infants.

Exposure to intrauterine inflammation leads to impaired function and altered structure in the preterm heart of fetal sheep.

Intrauterine inflammation is a major contributor to preterm birth and has adverse effects on preterm neonatal cardiovascular physiology. Cardiomyocyte maturation occurs in late gestation in species such as humans and sheep. We tested the hypothesis that intrauterine inflammation has deleterious effects on cardiac function in preterm sheep which might be explained by altered cardiomyocyte proliferation and maturation. Pregnant ewes received an ultrasound-guided intra-amniotic injection of lipopolysaccharide (LPS) or saline 7 days prior to delivery at day 127 of pregnancy (term 147 days). Cardiac contractility was recorded in spontaneously beating hearts of the offspring, perfused in a Langendorff apparatus. Saline-filled latex balloons were inserted into the left ventricle (LV) and right ventricle (RV). Responsiveness to isoprenaline and stop-flow/reperfusion was assessed. In other experiments, hearts were perfusion-fixed, and cardiomyocyte nuclearity, volume and number were determined. ß-Adrenoceptor mRNA levels were determined in unfixed tissue. In hearts of LPS-exposed fetuses, contractility in the LV and RV was suppressed by ~40% and cardiomyocyte numbers were reduced by ~25%. Immature mono-nucleated cardiomyocytes had lower volumes (~18%), whereas mature bi-nucleated cardiomyocyte volume was ~77% greater. Although basal coronary flow was significantly increased by 21±7% in LPS-exposed hearts, following ischaemia/reperfusion (IR), end-diastolic pressure was increased 2.4±0.3-fold and infarct area was increased 3.2±0.6-fold compared with those in controls. Maximum responsiveness to isoprenaline was enhanced by LPS, without an increase in ß-adrenoceptor mRNA, suggesting altered second messenger signalling. Intrauterine inflammation altered cardiac growth, suppressed contractile function and enhanced responsiveness to stress. Although these effects may ensure immediate survival, they probably contribute to the increased vulnerability of organ perfusion in preterm neonates.

Respiratory support for premature neonates in the delivery room: effects on cardiovascular function and the development of brain injury.

The transition to newborn life in preterm infants is complicated by immature cardiovascular and respiratory systems. Consequently, preterm infants often require respiratory support immediately after birth. Although aeration of the lung underpins the circulatory transition at birth, positive pressure ventilation can adversely affect cardiorespiratory function during this vulnerable period, reducing pulmonary blood flow and left ventricular output. Furthermore, pulmonary volutrauma is known to initiate pulmonary inflammatory responses, resulting in remote systemic involvement. This review focuses on the downstream consequences of positive pressure ventilation, in particular, interactions between cardiovascular output and the initiation of a systemic inflammatory cascade, on the immature brain. Recent studies have highlighted that positive pressure ventilation strategies are precursors of cerebral injury, probably mediated through cerebral blood flow instability. The presence of, or initiation of, an inflammatory cascade accentuates adverse cerebral blood flow, in addition to being a direct source of brain injury. Importantly, the degree of brain injury is dependent on the nature of the initial ventilation strategy used.

Post-implementation review of pulse oximetry screening of well newborns in an Australian tertiary maternity hospital.

AIM: Despite there being evidence that pulse oximetry screening is better than clinical examination alone in early detection of CHD, implementation has been slow. The aim of this paper was to evaluate the practice after its implementation into routine care at Royal Prince Alfred Hospital in 2008. METHODS: A single pulse oximetry measurement was incorporated in the routine discharge newborn examination or, with early discharge, as a part of the Midwife Discharge Support Programme. An oxygen saturation level greater than or equal to 95% was considered normal, and a level less than 95%, confirmed on a repeat measure, triggered a review and examination by a consultant neonatal paediatrician. The saturation levels were recorded in the hospital database. Ascertainment of major CHD requiring surgery in the first 12 months was performed by searching the cardiac surgery database of the Heart Centre for Children. RESULTS: A total of 18 801 babies were screened over a 42-month period. Of these, four babies with major CHD were diagnosed prior to discharge with the main clinical alert resulting from routine pulse oximetry screening (true positive). Of the 11 cases with saturation <95% but no CHD (false positive cases), six had respiratory pathology. One baby with normal saturation level needed surgery in the first year for a large ventricular septal defect (false negative). The false positive rate of pulse oximetry screening for CHD was 0.13% with sensitivity 80%, specificity of 99.8%, a positive predictive value of 13.3% and a negative predictive value of 99.9%. Nine additional echocardiogram were required over 42 months. CONCLUSIONS: These post-implementation data confirm that pulse oximetry screening increases early diagnosis of major CHD as well as other important pathology with a very low false positive rate and minimal requirement for extra echocardiograms. Pulse oximetry screening of apparently well newborns should become a standard of care.

Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension.

Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.